Calpain and calpastatin activity in the optic pathway.

The levels of the neutral proteolytic enzymes calpains and their endogenous inhibitor calpastatin were determined in the retina and in the retrobulbar optic pathway in the albino rabbit. The highest level of calpains was observed in the optic nerve with decreasing levels in the optic tract and superior colliculus. The level of calpastatin in the retina was very low compared to that in the optic nerve and tract and other parts of the nervous system.